C++中UNIX时间戳与日期互转

C++中UNIX时间戳与日期互转

1. 使用time.h头文件
2. localtime 可以把时间戳转为 tm 结构体, tm结构体中可以格式化输出时间
3. mktime可以把tm结构体转为时间戳
4. tm 结构体中: year需要+1900, tm_mon的范围是0-11, tm_mday的范围是1-31
   

   struct tm
   {
       int tm_sec;   // seconds after the minute - [0, 60] including leap second
       int tm_min;   // minutes after the hour - [0, 59]
       int tm_hour;  // hours since midnight - [0, 23]
       int tm_mday;  // day of the month - [1, 31]
       int tm_mon;   // months since January - [0, 11]
       int tm_year;  // years since 1900
       int tm_wday;  // days since Sunday - [0, 6]
       int tm_yday;  // days since January 1 - [0, 365]
       int tm_isdst; // daylight savings time flag
   };

5. 示例代码
   

   #define _CRT_SECURE_NO_WARNINGS
   
   #include
   #include
   #include 
   
   using namespace std;
   
   void int_to_time( long long int u)
   {
       tm * lt =  localtime (&u);
       printf ( "%d-%02d-%02d %02d:%02d:%02d\n" , lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday, lt->tm_hour, lt->tm_min, lt->tm_sec);
   }
   
   tm * build_string_line(string s)
   {
       int year, month, day, hh, mm, ss;
       int _e =  sscanf (s.c_str(),  "%d-%d-%d %d:%d:%d" , &year, &month, &day, &hh, &mm, &ss);
       tm * lt =  new tm ();
       lt->tm_year = year - 1900;
       lt->tm_mon = month - 1;
       lt->tm_mday = day;
       lt->tm_hour = hh;
       lt->tm_min = mm;
       lt->tm_sec = ss;
       return lt;
   }
   
   void time_to_int( tm * lt)
   {
       //printf("%d-%02d-%02d %02d:%02d:%02d\n", lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday, lt->tm_hour, lt->tm_min, lt->tm_sec);
       long long int u2 =  mktime (lt);
       printf ( "%lld\n" , u2);
   }